Furnace



A. NILSON.

FURNACE.

APPLICATION FILED JUNE 24,1920.

'ELAMAQQ; mama Oct. 311, 1922,

Patented Elli, i922.

lane? AND'EEVJ NILSQTN, OF CHICAGO, ELLIN 01S, ASSIGNOR T0 EUREKA $1LIOKELESS FURNACE (30., 0F CEICAGO, ILLINOIS.

FUEINAGE.

Application filed June 24, 1920. Serial No. 391,383.

T 0 all whom it may concern:

Be it known that 1, ANDREW NILsoN, a citizen of the United States, residing at Chicago, in the county of Cool; and State of Illinois, have invented a certain new and useful Improvement in Furnaces, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming apart of this specification.

This invention relates to furnaces and has for its object the provision of means to in crease the efiiciency of the furnace and to provide substantially smokeless combustion of the fuel.

The invention contemplates obtaining this result by the interposition of a battle wall or arch which divides the fuel chamber located above the grate into two compartments one of which is forwardly thereof and the other rearwardly thereof, the forward compartment forming the fire box and the rearward compartment the combustion chamber of the furnace. The baffle wall extends from side to side of the furnace and downwardly from the roof of the fuel chamber toward the grate. However, a space is left between the bottom of the battle wall and the grate that extends the full width of the grate. /Vhen fuel is put in the furnace it is thrown against the baffle wall and when the introduction of fuel is completed the bafie wall closes and seals the space upwardly from the top of the fuel to the roof of the fuel chamber, except for certain passages extending through the baffle wall.

The coal. that is located rearwardly of the battle wall and the combustion chamber slopes downwardly from the baffle wall to the rear end of the grate and li s in such a position as it assumes due to the action of gravity.

The purpose of providing a baffle wall is to lead the gases distilled from the fuel through the baflie wall to heat the same and through the combustion zone in the combustion chamber where the same are heated to a very high temperature and are completely consumed.

It has been found by a large number of experiments with arches of various dimensions and in various positions in the fuel chamber that the desired result of obtaining complete combustion in the combustion chamber could not be obtained except by providing the arch at a certain definite distance from the rear wall of the fuel chamber proportionately to the size of the grate and the bafiie wall a certain definite distance above the upper surface of the grate in proport on to the size of thgrate. The best location of this battle wall and its distance Irom the grate have been found by these various experiments and while slight variations in dimensions from the best location of the baffle wall will produce results up pro nmating those desired, any substantial variation therefrom does not produce satisfactory results.

The particular advantages and objects of the invention will be more clearly understood as the description ofthe accompanying drawingsproceeds, in which is shown the preferred structure for the furnace.

In the drawings:

dug. l is a longitudinal vertical sect onal view of the fuel chamber and asso ciated parts of a furnace constructed in accordance with my invention, certain portioi s of the furnace being broken away,and

F 1g. 2 is a horizontal section taken on line 2-2 of Fig. l.

The improved furnace comprises a fuel chamber 3 having the roof l, firing doors 5 in the front wall thereof, a rear wall 6, a grate 7 of any desired construction, formingthe bottom of said fuel chamber and separating the same from the ashpit 8.

The water containing parts of the furnace may be of any of the well. known types, one of them being shown in the accompanying drawing. The fuel chamber 3 is divided into a fire box 9 and a combustion chamber 10 by a baffle wall 11 which extends from the roof of the furnace downwardly toward the grate 7. The baffle wall 11 is made of ceramic material and is supported by a member 12 that contains water and is connected with the water containing portions of the furnace. The details of the structure of this baffle wall are preferably the same as is shown in my Patent l lo. 1,368,005, patented Dec. 21, 1920. The action of the baffle wall is to close the space above the fuel designated by the numeral 13 except for the passages l4: extending therethrough which passages cause any cold air circulating above the fuel 13 in the lire box 9 to be thoroughly heated before entering the combustion chamber 10 and to be mixed with the gases distilled from the coal 13 in the fire box 9. Except for the passages 14: which serve largely to prevent cooling of the furnace by cold air in the upper portion of the fire box 9 and to prevent explosions of the mixture of gases and air in the upper part of the fire box, the only means of communication between the fire box and the combustion chamber is through the coal under the baiiie Wall. a

It will be seen upon an inspection of 1 that the only means of exit of the gases and products of combustion passing under the battle Wall are through the restricted opening between the rear wall of the furnace 6 and the bafiie Wall 11. at the lower portion thereof and it has been found very important to properly proportion this space to that under the baffle wall. As the air supplied from the ashpit 8 to the combustion chamber 10 practically all passes through the grate area under the combustion chamber and as this air promotes the active combustion of the fuel, and the gases distilled therefrom, over the entire grate area, the proper proportioning of this grate area to theentlre grate area is very important. This is true because the only place where active combustion occurs in the furnace is in the combustion chamber, the'combustion in the fire box being very slow and more on the order of a coking operation.

In order to obtain the proper location for this baiiie wall a large number of experiments have been conducted and it has been found that when the baiiie wall is located so that the distance between the rear thereof and the rear wall of the furnace is approximately one-fifth of the entire length of the grate from the front to the rear of the furnace the best results are obtained. The exact ratio of the distance from the rear wall of the furnace t the rear of the baffle wall to the distance from rear wall of the furnace to the front wall thereof has been found to be as one is to L66. Thus the grate area under the combustion chamber will be to the area of the entire grate surface 1 is to 4.66. By varying the height of the bottom of the baffle wall which constitutes the water containin member 12 it has been found that the best results are obtained when the area of the opening under the baffle Wall is approximately onefourth of-the entire grate area or in other words, when the distance from the top of the grate to the bottom of the baffle wall is approximately one fourth of the distance from the rear of the furnace to the front wall thereof. The exact ratio of the distance from the grate to the bottom of the baiile wall to the distance from the front wall to the rear Wall'of the furnace that gives the greatesteiliciency has been found to be as 1 is to 3.73 which makes the ratio of the area under the baffle wall to the area of the entire grate surface substantially as 1 is to 3.73. I

As pointed out above any substantial variation from these proportions has been found by many careful experiments to produce no beneficial results that would otherwise be obtainable from the baiiie wall. The efficiency of the furnace is not greatly increased unless these proportions are substantially adhered to and smokeless combustion does not result unless the baffle wall is positioned substantially as has been described in the specification.

It has been found by the particular arrangement set forth above that an evaporati've efficiency of approximately seventy per cent has been obtained under actual operative conditions as compared with an efficiency of approximately forty per cent that is obtained with the average low pressure heating plant. It being understood that this arrangement is particularly advantageous when used in low pressure furnaces as it greatly increases the efficiency thereof and makes it possible to use lower grade fuels than are ordinarily used without producing an undesirable amount of smoke.

Having thus described my invention I desire to have it particularly understood that I do not intend to limit myself to the exact details of the structure shown and described except as defined in the following claims.

1. In a furnace, a fuel chamber, an ashpit, a grate separating said fuel chamber and ashpit and extending the full length of said chamber and a baffle wall extending down wardly from the roof of said fuel chamber toward saidgrate, said baffle wall being spaced from said grate and dividing said fuel chamber into a portionrearwardly of said baflie wall providing a combustion chamber, and a fire box forwardly of said baffle wall, said combustion chamber being substantially one-fifth of the size of the entire fuel chamber and the distance of the baffle Wall from said grate being substantially one-fourth of the length of the grate.

2. In a furnace, a fuel chamber, an ashpit, a grate separating said fuel chamber and ashpit and a battle wall extending downwardly from the roof of said fuel chamber toward said grate, said baffle wall being spaced from said grate, to provide an opening between said grate and baffle wall and dividing said fuel chamber into a portion rearwardly of said'baflle wall providing a combustion chamber, and a fire box forwardly of said bafiie wall, said combustion chamber being substantially one-fifth the size of the entire fuel chamber andthe area of the opening under, said baiiie wall being substantially one-fourth of the entire grate area.

3. In a furnace, a fuel chamber, an ashpit. a grate separating said fuel chamber and naea-aeo ashpit and a baffle wall extending downwardly from the roof of said fuel chamber toward said grate, said bafiie wall being provided with a plurality of passages therethrough for carrying the gases from above the fuel in the forward part of said chamber downwardly to a point rearwardly of said wall adjacent the bottom thereof, said bafile wall being spaced from said grate, to pro vide an opening between said grate and indie wall and dividing said fuel chamber into a portion rearwardly of said baffle wall providing a combustion chamber, and a fire box forwardly of said baffle wall, the grate area under the combustion chamber being substantially one-fifth and the area of the opening under the baffle wall being substantially one-fourth of the entire grate area.

4. In a furnace, a fuel chamber, an ashpit,

a grate separating said fuel chamber and ashpit and a baflle wall extending downwardly from the roof of said fuel chamber toward said grate, said baffle wall being spaced from said grate to provide an opening between said grate and bafiie wall, and dividing said fuel chamber into a portion rearwardly of said bafiie wall providing a combustion chamber and a fire box forwardly of said baffle wall, the ratio of the grate area under the combustion chamber to the entire grate area being substantially as 1 is to 4.66 and the ratio of the area of the opening between said grate and baffle wall to the total grate area being substantially as 1 is to 3.73.

hi witness whereof, I hereunto subscribe my name this 14th day of June, A. D, 1920.

ANDREW NILSON. 

